Solriamfetol Shows No Significant Impact on Nocturnal Sleep Parameters in OSA-Related Excessive Daytime Sleepiness

A recently published exploratory analysis of a randomized phase 3 trial (NCT06103825) showed that solriamfetol (Sunosi; Axsome Therapeutics) did not result in significant or consistent changes in polysomnography (PSG) parameters compared with placebo for treating excessive daytime sleepiness (EDS) among Chinese patients with obstructive sleep apnea (OSA). These findings suggest that morning administration of the wake-promoting agent may improve EDS without significantly affecting nocturnal sleep quality.¹

Among 201 participants included in the analysis (solriamfetol, n = 101; placebo, n = 100), the mean total sleep time (TST) at baseline was similar between groups (solriamfetol, 402.65 [SD, 42.59] minutes; placebo, 406.11 [SD, 39.88] minutes). Findings showed that TST decreased in both groups at 2 weeks (least squares mean difference, −2.48 minutes; 95% CI, −16.10 to 11.14). At 5 weeks (−2.81 minutes; 95% CI, −15.58 to 9.95) and 12 weeks (−1.21 minutes; 95% CI, −12.43 to 10.01), TST increased in the solriamfetol group.

Researchers observed no significant between-group differences in N1, N2, or N3 sleep stages at any time point, except for a difference in N1 sleep at 2 weeks (9.44; 95% CI, 3.45-15.43; P = .0022) and in N3 sleep at 5 weeks (−7.79; 95% CI, −14.41 to −1.18); P = .0212). Notably, the authors reported that 3 cases of insomnia-related adverse events occurred during the study, all of which were observed in the placebo group.

“In this study involving Chinese patients with OSA-EDS, treatment with solriamfetol showed no significant effects on nocturnal sleep or wake parameters. Importantly, this lack of observed impact on nighttime sleep reflects the timing of morning administration, rather than indicating an absence of any potential drug influence on nocturnal sleep,” senior author Yongmin Ding, MD, Department of Neurology at The Second Affiliated Hospital of Nanchang University in China, and colleagues, wrote.¹

The current analysis used data from a 12-week, randomized, double-blind, placebo-controlled, multicenter, parallel-arm phase 3 trial evaluating the efficacy and safety of solriamfetol in Chinese patients aged 18 to 75 years with OSA and EDS.² The trial, conducted across 26 centers in China between July 17, 2023, and August 19, 2024, had 3 phases: a screening and baseline period of up to 60 days, a 12-week treatment period, and a 2-week safety follow-up. After completing screening and baseline assessments, eligible participants were randomly assigned in a double-blind manner to receive solriamfetol 150 mg or placebo in a 1:1 ratio.

The coprimary efficacy end points of the trial were changes from baseline to week 12 in mean sleep latency on the Maintenance Wakefulness Test and Epworth Sleepiness Scale scores. Exploratory end points of the current analysis included changes in PSG parameters at 2, 5, and 12 weeks, which were unadjusted and considered hypothesis-generating. Sleep quality parameters included TST and wakefulness after sleep onset (WASO), whereas respiratory parameters included mean and minimum oxygen saturation (SaO₂), apnea index, and apnea-hypopnea index (AHI).

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Compared with baseline (solriamfetol, 64.74 [SD, 40.67] minutes; placebo, 60.05 [SD, 35.77] minutes), WASO increased at week 2 in both groups, with a mean change of 5.82 (SD, 43.43) minutes in the solriamfetol group and 8.02 (SD, 37.75) minutes in the placebo group. At subsequent time points, both groups demonstrated modest reductions in WASO, including decreases of 3.81 (SD, 35.91) minutes at 5 weeks in the solriamfetol group compared with 3.63 (SD, 33.91) minutes in the placebo group, and further reductions of 6.22 (SD, 35.14) minutes versus 1.30 (SD, 36.35) minutes, respectively, by 12 weeks.

Findings revealed that small changes were observed over time in both groups, compared with baseline mean SaO₂ values (solriamfetol, 95.17% [SD, 1.74]; placebo, 95.06% [SD, 1.86]). In the solriamfetol group, mean SaO₂ decreased by 0.14%, 0.34%, and 0.32% at 2, 5, and 12 weeks, respectively. In the placebo group, authors noted that the mean SaO₂ increased by 0.04%, 0.14%, and 0.04% at the same time points, respectively.

Baseline mini SaO₂ was similar between participants treated with solriamfetol (84.83% [SD, 7.89]) and those receiving placebo (84.02% [SD, 10.4]). Compared with baseline, solriamfetol was associated with a slight numerical increase in mini SaO₂ at week 2 (0.30%), followed by small decreases at week 5 (0.17%) and week 12 (0.61%). In the placebo group, minimal numerical increases were observed at weeks 2 (1.03%), 5 (1.06%), and 12 (0.57%).

Additional results demonstrated that at 2 weeks, AHI decreased by 0.16 (SD, 10.14) in the solriamfetol group, followed by increases of 0.67 (SD, 9.77) at 5 weeks and 0.89 (SD, 10.85) at 12 weeks compared with baseline. In the placebo group, AHI increased by 1.11 (SD, 15.75) at week 2, followed by decreases of 1.76 (SD, 10.42) at week 5 and 1.37 (SD, 9.85) at 12 weeks.

“This clinical trial monitored nocturnal respiratory indicators in participants with varying adherence to treatment, including those who declined basic OSA treatment,” Ding et al noted. “Overall, these results underscore the role of morning administration of solriamfetol as a reliable therapeutic option for improving wakefulness without compromising on sleep quality.”

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REFERENCES
1. Wang F, Deng L, Xie L, et al. Impact of solriamfetol treatment on sleep quality in Chinese patients with OSA-EDS: results of a randomized controlled trial. Front Med (Lausanne). 2026;13:1712097. Published 2026 Feb 18. doi:10.3389/fmed.2026.1712097
2. Cheng H, Deng L, Meng Z, et al. Efficacy and Safety of Solriamfetol on Excessive Daytime Sleepiness Associated with Obstructive Sleep Apnea in China: A Phase 3, Multicenter, Double-Blind, Placebo-Controlled Randomized Clinical Trial. CNS Drugs. 2026;40(1):83-98. doi:10.1007/s40263-025-01232-1